Factors Affecting Overwintering Success Of Spathius Galinae, A Parasitoid Of The Invasive Emerald Ash Borer (Agrilus Planipennis)
Date
2022-05
Authors
Journal Title
Journal ISSN
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Publisher
University of Delaware
Abstract
Spathius galinae Belokobylskij is one of a few parasitoid wasps used as a biocontrol
agent against the invasive emerald ash borer (Agrilus planipennis Fairmaire), a
destructive beetle that has killed tens of millions of ash trees in the U.S. S. galinae are
known to overwinter as prepupae in silken cocoons, but little is known about the
overwintering success of these parasitoids at earlier life stages. Logs containing three
different life stage treatments of S. galinae (early instar larva, mid instar larva, and
prepupa) were placed in jars and deployed in two different microhabitat sites (urban
woods and mature woods). The logs were deployed in late fall, remained in the field
through winter, then S. galinae emergence was recorded in spring. Parasitoids in the
warmer urban site emerged an average of 14 days earlier than parasitoids in the cooler,
shaded mature woods site. S. galinae from all three life stage treatments successfully
emerged, although the exact effect of life stage on overwintering success is not
completely clear. Researchers in the future can release S. galinae for biocontrol
through mid and late fall, but another study should be conducted to determine if young
larval S. galinae have any less overwintering success than prepupae.
Description
Keywords
Wasps, Life stage, Biocontrol